Shares of Aveo Pharmaceuticals Inc. plummeted 31.3 percent Tuesday after the Food and Drug Administration said another clinical trial may be needed to weigh the risks and benefits of the Cambridge company’s kidney cancer treatment.

The development raised the prospect of a delay in the FDA’s ruling on Aveo’s experimental drug for advanced renal cell carcinoma. The agency had been scheduled to decide by July 28 whether to approve the drug for sale in the United States. More than 200,000 people worldwide suffer from renal cell carcinoma, and at least 12,000 new US cases are diagnosed each year.

Aveo executives are scheduled to meet with an FDA advisory committee Thursday to argue for speedy approval. But in a briefing document released Tuesday, federal regulators suggested the findings of a late-stage clinical trial with 517 patients demonstrated the drug — now called tivozanib — slowed progression of the disease, but also raised questions about whether it improved patient survival rates more than a medicine already available.

That drug, Nexavar, one of several on the market to treat the same kind of kidney cancer, was approved by the FDA in 2007.

Get Business Headlines in your inbox:

The Globe's latest business headlines delivered every morning, Monday through Friday.

It is comarketed by Onyx Pharmaceuticals Inc. and Bayer HealthCare Pharmaceuticals Inc. The global market for kidney cancer treatments is estimated at more than $2 billion annually.

FDA regulators said they would ask the advisory panel “whether this single trial is sufficient to support approval of tivozanib for the indication of treatment of patients with advanced renal cell cancer or whether an additional trial is necessary before considering marketing approval.”

That sent Aveo shares tumbling on the Nasdaq exchange. The stock fell 31.3 percent, or $2.33, to $5.11 a share, a three-year low, as analysts warned of heightened regulatory concerns.

Biotechnology analyst Howard Liang, managing director at the health care investment bank Leerink Swann in Boston, recently downgraded Aveo’s stock. In a note to investors Tuesday, he said the “dilemma facing the FDA and the committee” is reflected in the question before the panel: “Given the uncertainty in overall survival, and availability of multiple therapies, is another trial needed to better characterize the risk-benefit profile of tivozanib before approval can be considered?”

Aveo executives declined to discuss the FDA’s briefing document.

Vice president Robert Kloppenburg said they were preparing for Thursday’s advisory panel meeting.

“We look forward to walking the panel through the details of the data package in support of tivozanib for the treatment of advanced renal cell carcinoma, and addressing the agency’s questions in that forum,” Kloppenburg said in an e-mail.

A delay in the approval of tivozanib would also be a setback for the Japanese drug maker Astellas Pharma Inc., which has the rights to sell the treatment in Europe.

Aveo has been planning to create a sales force to market the kidney cancer drug in the United States.

BostonGlobe.com complimentary digital access has been provided to you, without a subscription, for free starting today and ending in 14 days. After the free trial period, your free BostonGlobe.com digital access will stop immediately unless you sign up for BostonGlobe.com digital subscription. Current print and digital subscribers are not eligible for the free trial.

Thanks & Welcome to Globe.com

You now have unlimited access for the next two weeks.

BostonGlobe.com complimentary digital access has been provided to you, without a subscription, for free starting today and ending in 14 days. After the free trial period, your free BostonGlobe.com digital access will stop immediately unless you sign up for BostonGlobe.com digital subscription. Current print and digital subscribers are not eligible for the free trial.